Let J be the intersection of the diagonals
[tex]pj = \frac{po}{2} = \frac{6}{2} = 3[/tex]
[tex]rj = \frac{rq}{2} = \frac{8}{2} = 4[/tex]
Applying the Pythagorean theorem:
[tex](pr) {}^{2} = (pj) {}^{2} +( {rj})^{2} \\ pr = \sqrt{(3) {}^{2} + (4) {}^{2} } = \sqrt{9 + 16} \\ pr = \sqrt{25} = 5[/tex]
